Battery-operated receiver



May 9, 1939. P. F. e. HOLST 2,157,899

BATTERY-OPERATED RECEIVER Filed Oct. 19, 1957 2 Sheets-Sheet 1 II E f Zhwento: Paul 1'? G. Hal-sf y 1939- P. F. e. HOLST 2,157,899

BATTERY- OPERATED RECEIVER Filed Oct. 19, 1937 2 Sheets-Sheet 2 &

3nventor Pal/Ll Halsi k Patented May 9, 1939 UNITED STATESv PATENT ()FFECE BATTERY-OPERATED RECEIVER aware Application October 19, 1937, Serial No. 169,791

6 Claims.

The present invention relates to battery operated radio receivers and more particularly it relates to power supply circuits for such receivers, providing filament, anode, screen grid and biasing potentials and means for controlling the same.

It is an object of the present invention to provide an improved battery operated radio receiver wherein the power supply circuit and control 10 means therefor are simplified and combined for the effective control of battery power directly, or through a vibrator or inverter device.

By vibrator or inverter device is meant any electrical means such as a vibrating contact de- 1 vice, transformer controlled, thereby to raise the direct current supply voltage, such as is provided by an ordinary storage battery, to a higher value suitable for plate supply.

The present invention contemplates the operation of a radio receiver from a storage battery or the like, in connection with a vibrator or inverter device of the type above referred to, or alternatively in connection with an A battery for filament supply and ordinary dry cell B batteries or the like for plate, screen grid and bias supply.

In carrying into effect the objects of the invention, biasing batteries of relatively small size are incorporated directly in the receiver circuits whereby external connections thereto are eliminated, and because of the absence of current drain, long life is assured, substantially the same as that for the tubes which are also replaceable.

It is also a further object of the present invention, to provide in connection with a battery operated radio receiver, a power switch or control means for battery operation directly in the radio receiver itself, and plug connections therefor so arranged that for battery operation, the filament supply and B battery supply are controlled, while for vibrator operation the filament supply and vibrator low potential supply are controlled.

It is a still further object for the invention, to provide in the plug connection for the power switch or control means, a circuit arrangement whereby the output or power amplifier of the receiver may have applied thereto a higher voltage automatically when the vibrator connection is used, and whereby with such a higher voltage, a higher power output may be obtained, while at the same time a resistor filter may be inserted automatically in circuit with the lower voltage anode and screen grid circuits, not only to lower the voltage but also to produce an effective filter action in the plate supply circuit for the receiver.

These and other objects of the invention, and a further understanding of the same will be better understood from the following description, 5 when considered in connection with the accompanying drawings, and the scope of the invention will be pointed out in the appended claims.

Referring to the drawings,

Figure 1 is a schematic circuit diagram of a 1:) battery operated radio receiver provided with a power supply system and control means therefor embodying the invention, and

Figure 2 is a similar schematic circuit diagram of a vibrator power supply circuit adapted to be connected to the receiving system of Fig. l in accordance with the invention.

Referring to Fig. 1, the battery operated radio receiver circuit shown, comprises tuning elements represented by the rectangular enclosure 5. This may also be considered as including the frequency changing means of a superheterodyne type of receiver in which the frequency changer tube is indicated at 6. The tube 1 is an intermediate frequency amplifier and the tube 8 is a combined second detector and audio frequency amplifier, for applying signals to the audio frequency amplifier comprising the driver tube 9, and the push-pull output tube Ill which is coupled to a loudspeaker ll. Since the present invention is concerned only with the power supply to the filaments or heaters and to the anode, screen grid and bias circuits, the description herein will be limited thereto as the normal connections for a radio receiving system of the type shown is known and understood.

In the present example, two bias batteries [2 and I3 are included in the grid circuits for supplying fixed bias to the various tubes and these batteries are of relatively small size included within the receiver so that no external connections are required. This greatly simplifies the external connections and the construction of the receiver and requires, in the case of battery operation shown, only three external leads from the receiver as indicated at [4, l5 and IS.

The external leads are connected to internal circuits within the receiver as follows: A high voltage anode supply lead I! for the high power output tube Ill; a low voltage anode and screen grid supply circuit l8 for the remainder of the receiving system, the voltage on which for full power operation is normally relatively low with respect to the voltage required for the anode circuit IT; a filament or cathode heating circuit iii lead l9 which extends through all the filaments or cathodes of the receiver in parallel, and a common circuit return means which, in the present example, is provided by the chassis, the connections of which are indicated in the drawings by the ground connections 26, for example, as applied to the cathode heating circuit return leads. A ground connection is also shown at 2! in connection with one of the leads l5 external to the receiver.

The lead l9 and the circuit leads connected therewith may be considered as the high side of the cathode or filament heating circuit while the low side of said circuit is the ground or chassis indicated at 26 and ill, for example. This is also the low side of the plate and screen grid supply circuit or negative side thereof as is indicated by the lead l5, being connected to ground 2! and to the negative terminal 22 of the A or filament battery 23 and through a fuse 24 to the negative terminal 25 of the B battery which comprises three sections, 2E, 27 and 28, in series, these being the usual 45'voltblocks to provide a total or 135 volts maximum for most economical battery operation, while at the same time providing appreciable power output from the receiver. The A battery 23 may comprise any suitable number of storage cells, dry cells or an air cell battery suitable for the filament load of the receiver. A resistor 29 may be included in the lead Hi to the positive terminal 30 of the A battery to reduce the voltage to a proper value suitable for the filaments or cathodes of the receiving system.

Heretofore it has been the practice to include the power controlling switch of a battery operated receiver in the power cord or in connection with a plug-in cord external to the receiver, whereby a different switching or controlling means could be utilized for battery operation from that used for vibrator or power operation from a single storage battery. Further in ac cordance with the invention, the power switch or controlling means is placed and permanently included within the receiver. This is indicated at 3i and is the multiple circuit type comprising three switching sections 32, 33 and 34, each of which is provided with three contacts selectively connectable with .fixed contact elements 35 through movable contact elements represented at 3B in each'switch section.

The elements 36 are interconnected mechanically as shown by the dotted connection, to move together between a left hand or off position as shown, an intermediate or on position, and an extreme right hand or third position, for efiecting the various connections controlling the power circuits of the receiver and also for controlling the tone of the output as will hereinafter, be explained.

Iihe switch section 32 is connected between the filament or cathode heating supply circuit lead iii and positive A battery lead i6 through a terminal i8 011 the receiver. The switch section 33 is connected to additional terminals 4| and 42 on the receiver and the switch section 34 is connected to leads 43 and id for controlling the application of a capacitor 45 across the input circuit 16 of the'output tube Hi to control the high frequency tone of the output when the switch elements as are moved to the mid-position. The latter section, therefore, is not connected to external terminals for the receiver but is connected internally to the tone control circuit.

Further, external connections for the receiver are provided for the anode and screen grid potential supply circuit it, which is connected with a terminal indicated at 5?, and a terminal 68 is provided for the high potential anode supply lead l i for the output stage.

In addition, an external terminal 49 for the chassis or ground connection 2! and a terminal 56 is provided for external connections to the receiver. The latter terminal is connected through a resistor 5i of substantially 2.2 ohms to the lead ll]. This last connection will hereinafter further be described.

The leads I4, i5 and it are connected, respectively, with the terminals ii, id and l through a plug connection indicated at 52 adapted to engage said terminals and to provide the connections shown. Said plug connection also includes a short-circuiting element 53 for engaging and connecting together the terminals ti and 48, thus connecting the high potential anode lead i? with the low potential anode and screen grid supply lead it? whereby they receive the same anode potential for 3 battery operation, and further connecting said leads through the switch section 33 to the terminal 4! and to the external supply lead 54 which is connected to the high positive potential terminal 54 of the battery block 28.

Since the chassis 2i is connected through the terminal 59 with the lead l5 and the negative terminal 25 of the B battery, closing. the switch section 33 in either the intermediate or the extreme right position serves to connect the anode and screen grid circuits of the receiver with the high potential positive side of the B battery, the

negative side being connected with the cathodes which are grounded to the chassis.

Closing the switch. section in the intermediate or extreme right positions completes the filament or cathode heating circuit through the lead 46, the terminal 3$ and the lead lil through the chassis 2H and El, returning to the A battery through the terminal li? and the ead i5.

Closure of the switch section in the inter mediate position serves to reduce the high frequency tones by operation of the capacitor 45 in shunt with the audio frequency amplifier circuit, while in the extreme right hand position the full tone is restored. This section is added to the power switch for the purpose of reducing the number of controls required in the receiver and is only supplementary to the use of the power control switch or control means and its location within the receiver.

It should be noted that two pilot lamps 5'5 are provided in the receiver and controlled by a switch 56 to take current from the filament supply lead l9 and the chassis This arrangement is provided to permit the dial lamp or other tuning indicating means usually provided in a receiver to be illuminated only when tuning in, thereby to conserve the A battery power when operating the receiver between tuning adjustments and the like.

In the position shown, the switch or controlling element 3| is shown in the off or open circuit 7 position in which both the A battery or filament heating circuit, and the high potential 13 battery oranode and screen grid supply circuits are open, thereby to prevent current leakage from the high voltage battery through the various circuits and electrolytic capacitors of the receiver when not in use.

The advantages in providing separate terminals forthe power output and remaining anode and screen grid circuits, as well as for one section of the control switch, will be seen when considering the circuit of Fig. 2, to which attention is now directed.

Referring now to Fig. 2, along with Fig. l, the external connections for the receiver terminals 50, 40, 49, 4|, 42, 41 and 48 are shown for the operation of the receiver from a single power supply source such as an ordinary six volt storage battery 60 and a vibrator or inverter plate potential supply device 6|.

The battery or low potential supply terminals of the vibrator or inverter are indicated at 62 and 63, the former being connected to the battery 60 at the negative terminal 64 through a suitable high frequency filter 65, and the terminal 63 being connected to an intermediate positive terminal 66 on the battery 60 through leads 6? and 68 which may be formed as a twisted pair as indicated at 69. The leads 6'! and 68 for energizing the vibrator device are connected, respectively, to the external terminals 4| and 42 of the switch section 33 whereby the vibrator is energized from a four volt section of the battery upon operation of the switch 3| to close the contacts of the section 33.

The filament circuit of the receiver is energized from the remaining two volt section of the battery 6D in connection with the positive terminal 10 and a more negative terminal H and of the same potential as the terminal 66, the filament heating current being taken through leads 12 and 13 which are also preferably arranged as a twisted pair, as indicated at M, and connected with the terminals and 49, thus being under control of the switch section 32 in the same manner as for ordinary battery operation. In addition, the terminal 49 is connected with the terminal as indicated by the bridging connection 75, to eifect a shunt connection of the resistor 5|, within the receiver, across the filament supply circuit and the two volt section of the battery to equalize the load on the battery, as the vibrator or inverter tends to draw more current than the filament circuit, ordinarily. For the purpose of adjusting or balancing the load, the resistor 5| may be made adjustable as shown. It will be noted that the load of the resistor 5! is also controlled within the receiver by the filament control section 32 of the switch 3|.

It will also be noted that the vibrator control leads 61 and 68 are formed as a separate circuit and that the vibrator is connected separately to the battery 60, from the filament supply circuit loads '12 and 13, whereby electrical impulses from the vibrator, tending to cause disturbances in the receiver, are prevented from entering the receiver through the filament supply lead. The vibrator device or inverter may be of any suitable type, and accordingly it is not believed necessary to describe the specific embodiment shown which is of a well known type, it being understood that the vibrator mechanism 16 controls the reversals of the primary current and rectification of the secondary voltage from a step up transformer 11.

In accordance with the invention, however, it should be further understood that the transformer or the elements of the inverter device is so designed that the output potential at the output terminals 18 and 63, the latter being the common input terminal and grounded as indicated at 19 to the chassis, is such that a relatively high voltage is provided for the power output tube II] of the receiver with respect to the normal anode and screen grid potential required for the remainder of the receiver and in connection with the terminal 41.

In providing the potential relation above referred to, the high potential or positive terminal of the inverter is connected through a lead 19 with the terminal 48, an output filter for reducing the radio frequency interference being provided as indicated at 80. Between the output terminal of the filter BI and the low anode and screen grid potential supply terminal 4'! on the receiver a relatively high resistance 82 is provided not only for reducing the potential at the terminal 41 materially and in the present example to substantially 135 volts in conjunction with the cap 8, but also to effect a filtering action in connection with the capacitor 85, Fig. l, and thereby to prevent interaction between the output circuit and the remainder of the receiver, anode and screen grid circuits, and a better filtered supply voltage. It has been found that by utilizing a relatively high voltage for the output tube, for vibrator or inverter operation, the simple resistor form of filter may be provided to effect the desired filtering action at low cost. This also results in a higher power output for the receiver through the use of a higher voltage at the vibrator output positive terminal 18. This voltage may be substantially 180 to 200 volts.

By providing the separate terminals 41 and 48 for the two anode circuits, the connection shown may be provided automatically through the use of a second plug connector indicated at 83 for carrying the vibrator connections shown, and applying them to the external terminals of the receiver. In this case the bridging connection i5 is included in the plug connector.

From the foregoing description, it will be seen that for ordinary battery operation, the filament supply and B potential supply for the receiver are controlled by two separate switch sections '32 and 33, which may be located permanently within and form part of the receiver, and that by providing an external connection for one of said sections, and suitable plug connections, the

same switch sections may be utilized for controlling the filament supply and vibrator or inverter supply without making any changes in the receiver or'without making any changes in the operation of the power switch located in the receiver.

Thus with this arrangement of circuits for the power supply of a battery operated receiver, the latter may readily be adapted for operation from either type of power supply without change other than to change the plug connection on the receiver, the separate plug connectors being connected to the power supply sources. This is a material advantage, particularly in connection with a receiver for portable use in an automobile,

in connection with the inverter with a storage battery as the only power source, and for the further use of the same receiver beyond the power lines in camps and other locations where the use of such receiver is desired and ordinary batteries may be provided. The change in connection from the one source of power supply to the other involves merely the change in the plug connections and no change in the circuits within the receiver or the operation or arrangement of the power switch.

I claim as my invention:

1. The combination with a battery operated radio receiver, of a switch in said receiver controlling the cathode heating current thereto, means providing a second switch connected with and conjointly operable with the first named switch having external circuit terminals, means providing high voltage and low voltage anode supply circuits for said receiver having external terminals, means providing plug connections with switch having external circuit terminals, means providing high voltage and low voltage anode supply circuits for said receiver having external terminals, means providing plug connections With said terminals whereby said circuits are energized through said last named switch, means providing additional plug connections with said terminals for connecting said second switch and said anode circuits with circuits external to said receiver, a vibrator-inverter device providing one of said external circuits in connection with said second switch for energizing said device through said switch, and said device having high voltage and low voltage output terminals and a resistance filter element connected therebetween having external circuit connections through said last named plug connection with the high and low voltage anode circuits of said receiver.

3. The combination with a battery operated radio receiver, of a power supply system therefor comprising a cathode heating circuit, a low voltage plate and screen grid supply circuit, a high voltage power output plate supply circuit, a power switch permanently located in said receiver having a switch section in said cathode heating circuit and having an additional switch section conjointly operable with said first named section, means including plug-in terminal connections on said receiver for said circuits and last named switch section, providing B battery supply control through said additional switch section jointly to said plate and screen grid circuits, means providing an alternative plug-in connection'with said terminals for an external circuit controlling connection with said additional switch section and separate potential supply connections for said low and high voltage plate circuits.

4. The combination with a battery operated radio receiver, of means providing a cathode heating circuit having a grounded chassis return connection, said circuit having external circuit terminals, a power control switch in said receiver having a switch section connected in the ungrounded side of said cathode heating circuit, means providing separate high and low voltage plate supply circuits for said receiver having external circuit terminals, a second switch section in said power switch conjointly operable with said first named section and having externalcircuit terminals, means including a plug-inconnector providing Abattery connections withsaid first named terminals, and a positive B battery potential connection through said second-switch section with said low and high voltage plate circuits, and said external terminals further being arranged to receive a second plug connection means for the control of the energizing of a vibrator-inverter device through said second switch section.

5. The combination with a battery operated radio receiver, of means providing a cathode heating circuit having external circuit terminals, a power control switch in said receiver having a switch section connected in said circuit-,-means providing separate high and low voltage plate supply circuits for said receiver having external circuit terminals, a second switch section in said power switch conjointly operable with said first named section and having external circuit terminals, means including a plug connector for said external terminals providing A battery connections with said first named terminals, and a positive B battery potential connection through said second switch section with said low and high voltage plate circuits, said external terminals further being arranged to receive a second plug connection means for'the control of a vibrator-inverter device and cathode heatingcircuit connections from separate sections of asingle storage battery, said last named means ineluding an external circuit for energizing said vibrator--inverter device in connection with said second switch section, and separate plate potential supply connections for saidlow and-high voltage plate supply circuits including a potential reducing resistor filter element for the low voltage plate supply circuit.

6. The combination as defined in claim 4, further characterized by the fact that said last named plug connection means includes connections for an external circuit with the external terminals of said second switch section for energizing said vibrator-inverter device, plate potential supply connections for said low and high voltage plate supply circuits including -a potential reducing resistor filter element, and a load resistor in said receiver for said cathode heating element and a-circuit through said plugconnection whereby said load resistor is connected 'in parallel with said cathode heating circuit, said resistor being adjusted to balance the load on the power supply battery between the cathode heating circuit and the'vibratorinverter supply device, and being further characterized by the fact that a filter capacitor operative in connection with said filter resistor for filtering the plate 00 current to said low voltage plate supply circuit is provided in said receiver.

PAUL F. G. HOLST, 

